An organic medium containing one or more metals of Group 8 may be obtained after chemical reactions in which a catalyst bearing such metal(s) is employed.
It is a drawback of the known methods for recovering such metals from organic reaction mixtures that their recovery is incomplete or laborious, particularly if the concentration of such metals in the mixtures is low.
It is an object of the present invention to separate said metals in a highly efficient manner from an organic medium.
In certain important aspects, the present invention accomplishes such separation by a process in which the metal compounds are extracted from the organic medium using an aqueous extractant phase containing a certain cyclic phosphite compound. Prior art relevant to such a process includes U.S. Pat. No. 4,496,768 which describes a process for the production of aldehydes by hydroformylation of alpha-olefins using a complex catalyst of rhodium with cyclic phosphites. The product aldehyde of this prior art hydroformylation process is separated from the rhodium/phosphite catalyst by distillation. British patent specification No. 889,338 describes the preparation of cyclic phosphites from triphenyl phosphites and pentaerythritol and states that the cyclic phosphite products are soluble in water. U.S. Pat. No. 4,523,036 and U.S. Pat. No. Re. 31,812 disclose hydroformylation processes carried out in the presence of water and water-soluble complexes of rhodium with certain cyclic phosphines. Products are recovered by phase separating the organic product from the aqueous solution of the rhodium/phosphine complex.